Peel the potatoes and chop them into small to medium dice.
Stir-fry the onions in a medium saucepan over medium-high heat (7 convection). Sauté for 5 minutes, until softened; add a couple of tablespoons of vegetable broth if they stick. Stir frequently.
Add the potatoes and season with salt and pepper. Add vegetable broth to cover the potatoes and bring them to a boil. Reduce heat to medium, cover, and simmer for 15 minutes, stirring a couple of times, until the potatoes are fork-tender.
Remove from heat and add the plant milk to the saucepan.
Using an immersion blender, blend the vegetables and liquids until smooth. Alternatively, you can place the contents in a blender until smooth, holding the lid with a tea towel since hot liquids tend to explode when mixed in a blender. Taste and adjust seasonings as desired.
Stir additional optional ingredients until well combined and serve with your favorite toppings.